However independent experts said the method was flawed and provided a weak link at best.

Around 2m people in Britain have type 2 diabetes and many have not yet been diagnosed, figures show.

Author Dr Ariel Beresniak, wrote in the journal: "The number of factors contributing to the growth of diabetes and obesity in the world confirms that ‘correlation does not imply causality’, and that a significant linear correlation between tea consumption and diabetes prevalence does not imply that low tea consumption could cause diabetes."